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ABSTRACT Fothergill DM, Frederick CS, Hughes LM. Buoyant ascent rate profiles for the MK10 and MK11 submarine escape and immersion equipment. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):343-358. Introduction: Since the U.S. Navy transitioned from the MK10 to the MK11 submarine escape and immersion equipment (SEIE), there has been an increase in the incident rate of pulmonary barotrauma during submarine escape training. This study compares the ascent rate profiles of the MK10 and MK11 SEIE to determine if ascent rate differences between the escape suits are associated with increased pulmonary barotraumas. Methods: Buoyant ascent rates of the MK10 and MK11 SEIE were compared using weighted manikins equivalent to the 1st, 50th, and 99th percentile body weight of a submariner. Human ascents using the MK11 (n=126) were compared to human ascents in the same trainer wearing the MK10 (n=124). Results: Manikin mean ascent times were faster for the MK10 than the MK11 (5.19 seconds vs 5.28 seconds, p < 0.05). Terminal velocity (Vt) was affected by manikin weight (p < 0.001). Human trials confirmed the manikin results. The average mean ascent velocity for the MK10 group was 0.155 meters/ second faster than the MK11 group's mean ascent velocity (p < 0.001). Mean ascent velocity ..

ABSTRACT Hess HW, Schlader ZJ, Johnson BD, Pryor RR, Hostler D. Aerobic exercise performance is reduced following prolonged cold-water immersion. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):359-372. Background: We tested the hypotheses that self-paced aerobic exercise performance is reduced following four hours of cold-water immersion when breathing air and further reduced when breathing 100% oxygen (O2). Nine healthy adults (four women; age 24 ± 3 years; body fat 17.9 ± 6.4 %; VO2max 48 ± 9 mL·kg·minute-1) completed three visits: a no-immersion control trial and two experimental trials consisting of a four-hour cold-water immersion (20.1±0.3°C) either breathing air (FIO2 = 0.21) or O2 (FIO2 = 1.0). During the no-immersion control trial and following immersion in the experimental trials, subjects first completed a 60-minute ruck-march carrying 20% of body mass in a rucksack, immediately followed by an unweighted, self-paced 5-km time trial on a motorized treadmill. Core temperature, heart rate, and rating of perceived exertion were recorded every 1,000 meters during the 5-km time trial. Data are presented mean ± SD. Time trial performance was reduced following immersion in both the 100% O2 trial (32 ± 6 minutes; p=0.01) and air trial (32 ± 5 minutes; p=0.01) compared to the control trial ..

ABSTRACT López E, Rivera M, Cancelos S, Marín C. Case report of CT-guided lung biopsy complicated by air embolism. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):373-381. Objective: The presentation of a novel prospective treatment for scenarios where bubble presence in the bloodstream poses a clinical risk. The method relies on generating resonant acoustic standing waves within a limb to non-invasively accelerate the dissolution of bubbles present in the bloodstream via bubble rupture. Additionally, a preliminary assessment of the effects of the resonant acoustic waves and bubble rupture events on red blood cell viability is provided. Methods: Two semicircular piezoelectric (PZT) transducers electrically connected to each other were assembled around a small-girth segment of a rear thigh removed from a swine specimen. When driven at the frequency of electric resonance, this swine thigh and PZT transducer arrangement generates resonant acoustic standing waves within the swine thigh. Consequently, mechanical resonance of the system was non-invasively established by monitoring the electric response of the PZT to the applied frequency. The resonant acoustic field generated was used for the detection and rupture of bubbles that travel through a simulated blood vessel installed across the swine thigh. Two sets of experiments were carried out using this methodology, ..

ABSTRACT DeMis J, Keuski B, Due A. Hyperbaric treatment deviations for U.S. Navy divers: Spinal DCS. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):383-390. Introduction: The United States Navy (USN) developed and refined standardized oxygen treatment tables for diving injuries, but USN tables may not address all situations of spinal decompression sickness (DCS). We describe a detailed recompression treatment regimen that deviated from standard USN protocol for an active-duty USN diver with a severe, delayed presentation of spinal cord DCS. Case Report: A USN diver surfaced from his second of three dives on a standard Navy ‘no-Decompression’ Air SCUBA dive (Max depth 101 fsw utilizing a Navy Dive Computer) and developed mid-thoracic back pain, intense nausea, paresthesias of bilateral feet, and penile erection. Either not recognizing the con- stellation of symptoms as DCS and after resolution of the aforementioned symptoms, he completed the third planned dive (essentially an in-water recompression). Several hours later, he developed paresthesias and numbness of bilateral feet and legs and bowel incontinence. He presented for hyperbaric treatment twenty hours after surfacing from the final dive and was diagnosed with severe spinal DCS. Based on the severity of clinical presentation and delay to treatment, the initial and follow-on treatments were modified ..

ABSTRACT Conard, J. Altitude Diving on a Closed Circuit Oxygen Rebreather. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):391-393. Closed-circuit rebreather diving is becoming more common. Rebreathers are complicated, adding to the stress of diving. Also adding to this complexity in the presented case is diving at a high-altitude, cold-water reservoir in Colorado. One diver experienced an oxygen-induced seizure at depth. The other diver had a rapid ascent with loss of consciousness. In this case, two experienced divers recovered from a possible devastating dive. Fortunately, they both returned to their pre-dive baseline health. Dive plan- ning is important, but as in this case, dive execution is paramount. This is a clinical case for an uncommon event presenting to an emergency department. Keywords: altitude; atmosphere absolute (ATA); hyperbarics; carbon dioxide (CO2); open circuit (OC); oxygen closed-circuit rebreather (O2 CCR); partial pressure of oxygen (PO2); self-contained underwater breathing apparatus (scuba)

ABSTRACT Doenyas-Barak K, Kutz I, Lang E, Gabriela L, Efrati S. Memory surfacing among veterans with PTSD receiving hyperbaric oxygen therapy. Undersea Hyperb Med. 2024 Fourth Quarter; 50(4):395- 401. Introduction: Growing evidence demonstrates that hyperbaric oxygen therapy (HBO2) induces neuroplasticity and can benefit individuals with post-traumatic stress disorder (PTSD). The aim of the current study was to evaluate the rate and pattern of memory surfacing during the course of HBO2 among veterans with combat-related PTSD. Methods: In a post-hoc analysis of a prospective study of the effect of HBO2 on PTSD symptoms in veterans, we evaluated the rate and character of memory surfacing during the course of HBO2 treatment. The treatment consisted of 60 daily 90-minute sessions, at 2 atmospheres absolute (ATA) pressure and 100% oxygen. Results: For 10 (35.7%) of the 28 participants, surfacing of new memories was reported during the HBO2 treatment course. Memories surfaced mainly during the second month of the treatment, at the mean session of 30.5±13.2. For 9 of these 10 participants, prodromal symptoms such as distress, anxiety, or worsening depression were documented; and in four, somatic pain was reported prior to memory surfacing. The pain and distress of memory surfacing resolved over the course of one to ..

ABSTRACT Otsuka Y, Tomura S, Toyooka T, Takeuchi S, Tomiyama A, Omura T, Saito D, Wada K. Hyperbaric hydrogen therapy improves secondary brain injury after head trauma. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):403-411. Background: The pathophysiology of traumatic brain injury (TBI) is caused by the initial physical damage and by the subsequent biochemical damage (secondary brain injury). Oxidative stress is deeply involved in secondary brain injury, so molecular hydrogen therapy may be effective for TBI. Hydrogen gas shows the optimal effect at concentrations of 2% or higher, but can only be used up to 1.3% in the form of a gas cylinder mixed with oxygen gas, which may not be sufficiently effective. The partial pressure of hydrogen increases in proportion to the pressure, so hyperbaric hydrogen therapy (HBH2) is more effective than that at atmospheric pressure. Methods: A total of 120 mice were divided into three groups: TBI + non-treatment group (TBI group; n = 40), TBI + HBH2 group (n = 40), and non-TBI + non-treatment group (sham group; n = 40). The TBI and TBI + HBH2 groups were subjected to moderate cerebral contusion induced by controlled cortical impact. The TBI + HBH2 group received hyperbaric hydrogen therapy ..

ABSTRACT Murao N, Oyama A, Yamamoto Y, Funayama E, Ishikawa K, Maeda T. Efficacy of hyperbaric oxygen after microtia reconstruction using costal cartilage: A retrospective case-control study. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):413-419. Introduction: Microtia reconstruction with autologous costal cartilage framework grafting is challenging because the three-dimensional structure of the ear is highly complex, and meeting the high aesthetic demands of patients can be difficult. If the skin flap overlying the framework is thinned to achieve a smooth and accentuated outline, a poor blood supply in the thin skin flap may lead to skin necrosis, exposure of the framework, and poor surgical results. Hyperbaric oxygen (HBO2) therapy can promote the healing of complex wounds and flaps. This study sought to determine the effectiveness of HBO2 therapy for the prevention of postoperative complications after framework grafting in microtia reconstruction. Methods: We retrospectively evaluated postoperative complications and compared outcomes in pediatric patients who underwent costal cartilage grafting for microtia reconstruction at our institution between 2011 and 2015, according to whether or not they received postoperative HBO2 therapy. HBO2 therapy was applied once daily for a total of 10 sessions starting on the first postoperative day. Results: During the study period, eight patients received HBO2 ..

ABSTRACT Johnson-Arbor K. Treatment of pediatric cerebral radiation necrosis using hyperbaric oxygenation. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):421-424. Introduction: Cerebral radiation necrosis is rarely encountered in pediatric patients. This case report describes a child with cerebral radiation necrosis who was successfully treated using corticosteroids, bevacizumab, and hyperbaric oxygenation. Case report: A 3-year-old boy developed progressive extremity weakness six months after the completion of radiation therapy for the treatment of a neuroepithelial malignancy. Treatment with corticosteroids and bevacizumab was initiated, but his symptoms did not improve, and he was then referred for hyperbaric oxygen therapy. After completing 60 hyperbaric treatments, he experienced significant improvements in mobility, which remained stable over the next year. Discussion: Cerebral radiation necrosis typically presents in children with symptoms of ataxia or headache. Corticosteroids and bevacizumab are common treatments, but hyperbaric oxygen therapy has also been studied as a therapeutic modality for this condition. When considering the use of hyperbaric oxygenation in pediatric patients, careful attention to treatment planning and patient safety can reduce the risks of adverse events such as middle ear barotrauma and confinement anxiety. Conclusion: In addition to other available pharmacologic therapies, hyperbaric oxygenation should be considered for the treatment of pediatric patients with cerebral radiation necrosis. Keywords: ..

ABSTRACT Canarslan-Demir K, Ozgok-Kangal K, Saatci-Yasar A, Erdol MA, Koç B. Analysis of the cardiovascular effects of hyperbaric oxygen therapy in diabetic patients. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):425-431. During hyperbaric oxygen (HBO2) therapy in humans, there are changes in cardiovascular physiology due to high pressure and hyperoxygenation. Peripheral vasoconstriction, bradycardia, and a decrease in cardiac output are observed during HBO2 therapy. These physiological effects of HBO2 therapy on the cardiovascular system are tolerated in healthy people. However, patients with underlying cardiac disease may experience severe problems during HBO2 therapy, such as pulmonary edema and death. In addition, cardiac complications may occur in patients with diabetes mellitus (DM). Therefore, HBO2 therapy may negatively affect cardiovascular physiology in patients with DM. The present study aimed to examine the cardiovascular effects of HBO2 therapy in diabetic patients. The findings of NT-ProBNP, troponin I, and electrocardiography (ECG) of diabetic patients who applied to the Ministry of Health University Gülhane Training Research Underwater and Hyperbaric Medicine Clinic were compared before and after the first HBO2 therapy session. When ECG findings were analyzed at the end of a session of HBO2 exposure, a statistically significant increase was observed in the QTc and QTc dispersion measurements (p < ..

ABSTRACT Krimus L, Rizvi SH, Marinov A, Clarke H, Katznelson R. Hyperbaric oxygen therapy for treatment of COVID-19-related parosmia: a case report. Undersea Hyperb Med. 2023 Fourth Quarter; 50(4):433- 435. Parosmia is a qualitative olfactory dysfunction characterized by distortion of odor perception. Traditional treatments for parosmia include olfactory training and steroids. Some patients infected with COVID-19 have developed chronic parosmia as a result of their infection. Here, we present the case of a patient who developed parosmia after a COVID-19 infection that was not improved by traditional treatments but found significant improvement after hyperbaric oxygen therapy[A1]. Keywords: COVID-19; hyperbaric oxygen therapy; parosmia